1. Field of the Invention
The present invention is related to a process for recovering divinylarene dioxides, particularly divinylarene dioxides derived from divinylbenzene. More specifically, the present invention relates to a process for recovering a divinylarene dioxide from a crude feed stream, for example, a stream resulting from an epoxidation process for preparing a divinylarene dioxide.
2. Description of Background and Related Art
There are various known processes for preparing a divinylarene dioxide such as a divinylbenzene dioxide (DVBDO). For example, U.S. Pat. No. 2,977,374 (“the '374 patent”), incorporated herein by reference, discloses epoxidizing divinylbenzene (DVB) using peracetic acid in ethyl acetate and reports a DVBDO yield of 49 percent (%). The '374 patent teaches recovery of an epoxidized product by continuous distillation in two passes; removal of lights such as solvent and byproduct acetic acid in a first pass; and recovery of overhead product in a second pass. An example is provided in the '374 patent for DVBDO that describes two “stripper” passes to remove lights and a “flash distillation” to recover the product overhead. The '374 patent discloses obtaining a low DVBDO purity (59 weight percent) and a low yield as reported in the example; thus, the process described in the '374 patent results in neither a high distillation recovery nor a high purity product.
M. Worzakowska, J. Appl. Poly. Sci. (2007) vol. 103, pp. 462-469, incorporated herein by reference, discloses epoxidizing DVB using acetonitrile-hydrogen peroxide in the presence of a magnesium oxide catalyst and greater than a 4-fold molar excess of hydrogen peroxide to olefin. The above Worzakowska article does not describe the use of distillation, and only discloses that the epoxides are “separated from the solvents and byproduct”. However, given the recovered product purity is only about 45%, while starting with a 65% divinylbenzene raw material purity, this process has both a low product purity, and a low distillation recovery.
U.S. Pat. No. 4,304,639 (“the '639 patent”) discloses a process for the purification of olefin oxides and describes a continuous distillation scheme using a small amount of water and a side draw with decant. The process described in the '639 patent is directed to the preparation of propylene oxide (PO). DVBDO is listed as one of a long list of potential epoxides that can be prepared using the process described in the '639 patent. However, the description in the '639 patent is insufficient to enable the skilled artisan to determine how the process might result in high distillation recovery of DVBDO or high DVBDO purity.
EP0878471A1 (“EP471”) discloses reactive radiation-initiated or thermally-initiated cationically-curable epoxide monomers and compositions made from those monomers; and describes the synthesis of DVBDO using Oxone. The workup described in EP471 includes removal of solvents “in vacuo at 35° C.”, with no further purification. EP471 teaches that 5 mL of DVB (4.58 g) (theoretical product approximately 5.7 g) yields 4.92 g of product which is an overall yield of 86%. The description in EP471 is insufficient to enable the skilled artisan to determine the distillation recovery or the purity of the recovered product. The product, as described in EP471, is not separated from any heavies present, i.e., the process of EP471 does not provide a distillation or separation step in its disclosed process to achieve a high purity of divinylarene dioxide.
EP1841753B1 (“EP753”) discloses a process for the epoxidation of an olefin with an improved energy balance. The disclosure in EP753 is focused on preparing PO from propylene, but generally claims the epoxidation of an “olefin”. EP753 teaches DVB as an olefin. In addition, EP753 teaches using a dividing wall column, distillation, and “distillative separations processes” in the recovery description (the focus of EP753 is on recovery of unreacted olefin, solvent, and product). The description in EP753 is insufficient to enable the skilled artisan to determine or define a high distillation recovery or high DVBDO purity process.
WO 2010/101144A1 discloses epoxy resin composition and describes processes for epoxidation in general. One example describes synthesis of DVBDO using 30% peracetic acid in ethyl acetate. 300 g of DVB are used to produce 151.6 g of distilled DVBDO (only 41% overall yield). Separations are described as ethyl acetate removal by “reduced pressure distillation using an evaporator”. High purity product (97.1% area %) is obtained by “purification using distillation” (10 torr, 150° C.). The description of the separations in WO 2010/101144A1 is insufficient to enable the skilled artisan to determine distillation recovery, however given the low overall yield of the product; the distillation recovery of the product is low.
Bull. Chem. Soc. Jpn, 64, 3442-3444 (1991) discloses the effect of anions on the epoxidation of styrenes with H2O2 in the presence of ammonium heptamolybdate(VI) dioctylin oxide catalysts. The product recovered by the above process is only described as being “separated” and the highest DVBDO overall yield described is 9.9%.
U.S. Pat. No. 2,982,752 discloses a composition comprising a polyepoxide and divinylbenzene dioxide and describes epoxidation of divinylbenzene (DVB) using peracetic acid solution in acetone or ethyl acetate. The patent further discloses “isolation of epoxide product by fractional distillation”.
U.S. Pat. No. 2,924,580 discloses a divinylbenzene dioxide composition; however, there is no mention of how DVBDO is produced.
While the above processes for preparing a divinylarene dioxide are known, there is little attention paid to efficiently recovering the divinylarene dioxide product from a resultant crude feed stream containing divinylarene dioxide after the upstream reaction and processing for producing the divinylarene dioxide product is completed. None of the previously known processes described in the above references result in both a high distillation recovery and a high purity product. In addition, none of the above references teach a process including the recovery of monoepoxides at high recovery and/or high purity. In addition, none of the above references describe a process or conditions of a process to reduce the risk of runaway reaction. Furthermore, none of the above references describe a process that has been developed on an industrial scale for industrial use.
Previously, divinylarene dioxide process development by the industry focused on the production of vinyl arene oxide by oxidizing vinyl arenes to vinyl arene oxides. Known processes focused primarily with the chemistry of the reaction process and not the separations aspects of the process. Heretofore, a few known processes for the recovery of divinylarene oxides from a crude feed stream provided several disadvantages including (1) formation of heavies during the recovery process, (2) low recovery of product (e.g., less than (<) 85%) to achieve high product purity (e.g. greater than (>) 85%), (3) low purity of recovered monoepoxide by-product(s) (e.g., <85%), and/or (4) risk of a runaway reaction.
U.S. Patent Application Ser. No. 61/288,511 filed Dec. 21, 2009; and U.S. Patent Application Ser. No. 61/424,322 filed Dec. 17, 2010, disclose distillation of divinylarene epoxides. The above patent applications describe distillation of crude product to produce refined DVBDO at high purity, and conditions for temperature, pressure, and residence time. The above patent applications do not define a distillation recovery to achieve >85% purity of product; do not describe a distillation to achieve >85% purity and >85% recovery of monoepoxides; and do not describe the conditions required to reduce the risk of runaway reaction.